India's 50 fastest-growing tech companies have witnessed a decline in their three-year average revenue growth to 365% this year, against 383% recorded in 2014, according to a study.

Compared to 657% in 2013, the fall in revenue growth is even more alarming.

However, this year's list is topped by F1 Info Solutions & Services, a Mumbai-based warranty support and spare parts management solutions firms, which recorded a massive 3,961% growth in its revenue over the past three years, according to annual 'Deloitte Technology Fast 50' ranking.

VMukti Solutions (1,025 per cent), GreyCampus Edutech (832 per cent), Zomato Media (750 per cent), and Ozonetel Systems (715 per cent) were the other firms in the top 5 list, Business Standard reported.

Rajiv Sundar, programme director for Technology Fast50 India 2015, Deloitte Touche Tohmatsu India, doesn't agree with a slowdown in the revenue growth rates of the fastest-growing tech firms.

"If you remove some outliers that have done very well over the past three years, growth on the whole will be homogenous," he said.

The top 25 companies have posted growth rates of over 200% in 2015, while revenues of three-fourths of total firms in the study stood between Rs 5 crore and Rs 50 crore.

With 31 firms finding a place again in this year's list and 12 companies seeing an increase in their rank, Sundar said "this is a clear indicator that these businesses have a high degree of scalability and revenue sustainability."

"However, chasing growth year after year, without an eye on the profitability quotient, is not sustainable," he added.

Besides Zomato, mobile recharge platform FreeCharge is the new entrant among the consumer internet companies in the list.

FreeCharge, which was acquired by Snapdeal, stood at 11th spot in the rankings, with a revenue growth of 398% in the past three financial years.

Pune-based Tech Mahindra and Ashok Soota-promoted Happiest Minds are the two IT companies to appear in the list, standing at 23rd and 17th positions respectively.

While Tech Mahindra saw its revenue growth rising by 229% in the past three years, Happiest Minds saw 293% increase.

Companies in cloud technologies, online education and analytics segments "dominated" the top-20 list this year, while many IT services companies figured between 21st and 50th positions.